import org.apache.calcite.DataContext;
import org.apache.calcite.adapter.java.JavaTypeFactory;
import org.apache.calcite.linq4j.Enumerable;
import org.apache.calcite.linq4j.Linq4j;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.core.JoinRelType;
import org.apache.calcite.rel.logical.LogicalJoin;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.schema.SchemaPlus;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.sql.fun.SqlStdOperatorTable;
import org.apache.calcite.tools.Frameworks;

public class CalciteCrossJoinExample {
  public static void main(String[] args) {
    // Define two tables
    Enumerable<Object[]> table1 = Linq4j.asEnumerable(new Object[][]{{1}, {2}});
    Enumerable<Object[]> table2 = Linq4j.asEnumerable(new Object[][]{{'a'}, {'b'}});
    /*
    // Create a DataContext
    DataContext dataContext = createDataContext();

    // Create a RelNode corresponding to the CROSS JOIN operation
    LogicalJoin join = new LogicalJoin(
        null,
        null,
        dataContext,
        RelNode.EMPTY, // left input
        RelNode.EMPTY, // right input
        JoinRelType.INNER,
        Frameworks.newConfigBuilder().build().getTypeFactory().createSqlType(JavaTypeFactoryImpl.INSTANCE, 0),
        ImmutableBitSet.range(0, 0),
        SqlStdOperatorTable.CROSS_JOIN,
        ImmutableList.<RexNode>of(),
        "crossJoin"
    );

    // Execute the query and print the results
    Enumerable<Object[]> result = Linq4j.asEnumerable(join.collect()).select(x -> ((Object[]) x));
    result.forEach(x -> System.out.println(Arrays.toString(x)));
  }

  private static DataContext createDataContext() {
    // Define a schema with two tables
    SchemaPlus rootSchema = Frameworks.createRootSchema(true);
    rootSchema.add("table1", Linq4j.asEnumerable(new Object[][]{{1}, {2}}));
    rootSchema.add("table2", Linq4j.asEnumerable(new Object[][]{{'a'}, {'b'}}));

    // Create a DataContext with the schema
    return DataContext.ROOT.createChildContext(
        Frameworks.newConfigBuilder().defaultSchema(rootSchema).build());
  }
  */
  }
}